1. Technical Field of the Invention
The present invention relates to the formulation of an antagonist of CGRP (peptide derived from the calcitonin gene: Calcitonin Gene Related Peptide, or "CGRP") into cosmetic/pharmaceutical/dermatological compositions, in particular for topical application, for the treatment of certain disease states of the skin.
More especially, this invention relates to the topical, ingestible (oral) or injectable (enteral) treatment of lichens, in particular flat lichens and pigmentary lichens; prurigos and in particular actinic prurigo, Besnier's prurigo or Hebra's prurigo or strophulus or Hyde's prurigo; pruriginous toxidermias and severe pruritus, notably those afflicting blood dialysis patients and AIDS patients, and cholestatic or biliary pruritus. Pruriginous toxidermias occur in particular after absorption of medicaments; these disease states are very different from urticaria and do not entail any contact reaction.
2. Description of the Prior Art
It is known to this art to treat flat lichens and pigmentary lichens using local corticoids or those from PUVA therapy. Although, admittedly, corticoids are very effective in alleviating the symptoms, they have side effects which are often very deleterious, such as atrophies, especially mycotic or bacterial infections. PUVA therapy is the local irradiation of diseased skin with UVA radiation, after absorption of a photosensitizing substance (psoralen). This technique presents the serious drawback of a photoaging which is apt to produce skin cancers. Furthermore, this treatment is not ambulatory, requiring the patient to regularly visit a specialist center throughout the duration of the treatment, which is very restricting and limits his or her professional activity.
Prurigos are also treated by local corticoids, PUVA therapy or thalidomide. Local corticoids and PUVA therapy present the above drawbacks. Thalidomide presents the major disadvantage of being teratogenic, which prohibits its use in pregnant women. Furthermore, its very tightly controlled prescription (restricted to hospital doctors) limits its use.
Pruriginous toxidermias are currently treated by means of local corticoids and/or antihistamines: such treatment thus presents the same drawbacks as those indicated above.
Severe pruritus is also treated with local corticoids, with the same drawbacks as those indicated above.
Thus, serious need continues to exist in this art for a treatment of the aforesaid skin afflictions which does not have the above drawbacks/disadvantages.